The F5 SSL Orchestrator and Cisco Firepower Solution · 2018-08-14 · RECOMMENDED DEPLOYMENT PRACTICES F5 and Cisco Firepower SSL Visibility with Service Chaining 3 Introduction

RECOMMENDED DEPLOYMENT PRACTICES

F5 and Cisco FirePower SSL Orchestration with Service Chaining

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The F5 SSL Orchestrator and Cisco Firepower Solution:

SSL Visibility with Service Chaining for Advanced Malware Protection

March 2018

Contents Introduction ...............................................................................................................................3

The Integrated Solution ..............................................................................................................3 SSL visibility: How do we do it? ............................................................................................................ 4 SSL orchestration using security service chains .................................................................................... 5

Deployment Planning .................................................................................................................6 Sizing ................................................................................................................................................... 6 License components ............................................................................................................................ 7 Horizontal scaling ................................................................................................................................ 7 Traffic exemptions for SSL inspection................................................................................................... 8 Certificate requirements ...................................................................................................................... 9 IP addressing ....................................................................................................................................... 9 Deployment modes ........................................................................................................................... 10

Initial Setup ..............................................................................................................................11 Run the SSL Orchestrator Setup Wizard ............................................................................................. 12 Update the SSL Orchestrator version ................................................................................................. 15 Back up your F5 system configuration ................................................................................................ 17

Configuration for a Single F5 System with FirePOWER Services on Cisco ASA in L2 Mode

(Burrito Design) ........................................................................................................................18 Configure SSL Orchestrator ................................................................................................................ 19 Create layer 2 inline service ............................................................................................................... 23

Configuration for an F5 System with FirePOWER Services on Cisco ASA in L3 Mode ...............25 Create the layer 3 inline service ......................................................................................................... 25

Configuration for the F5 System with Cisco ASAs in TAP Mode ...............................................26 Create a receive-only service ............................................................................................................. 27

Alternative Architectures .........................................................................................................28 Two F5 systems with ASAs deployed as a service pool ....................................................................... 28 Two F5 systems with firewalls sandwiched in the decryption zone .................................................... 31 Creating service chains to link services............................................................................................... 34 Creating TCP service chain classifier rules .......................................................................................... 34

Handling NAT ............................................................................................................................37

Testing the Solution..................................................................................................................38


F5 and Cisco Firepower SSL Visibility with Service Chaining

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Introduction The Secure Sockets Layer (SSL) protocol and its successor, Transport Layer Security (TLS), have been widely

adopted by organizations to secure IP communications, and their use is growing rapidly. While SSL provides data

privacy and secure communications, it also creates challenges to inspection devices in the security stack when

inspecting the encrypted traffic. In short, the encrypted communications cannot be seen as clear text and are passed

through without inspection, becoming security blind spots. This creates serious risks for businesses: What if attackers

are hiding malware inside the encrypted traffic?

However, performing decryption of SSL/TLS traffic on the security inspection devices, with native decryption support,

can tremendously degrade the performance of those devices. This performance concern becomes even more

challenging given the demands of stronger, 2048-bit certificates.

An integrated F5 and Cisco Advanced Malware Protection (AMP) solution solves these two SSL/TLS challenges. F5®

SSL Orchestrator™ centralizes SSL inspection across complex security architectures, enabling flexible deployment

options for decrypting and re-encrypting user traffic. It also provides intelligent traffic orchestration using dynamic

service chaining and policy-based management. The decrypted traffic is then inspected by one or more Cisco next-

generation firewalls (NGFWs), which can prevent previously hidden threats and block zero-day exploits. The Cisco

Firepower Threat defense may be delivered using several combinations of Cisco Firepower and ASA platforms and

software images. This solution eliminates the blind spots introduced by SSL and closes any opportunity for

adversaries.

This guide provides an overview of the joint solution, describes different deployment modes with reference to service

chain architectures, recommends practices, and offers guidance on how to handle enforcement of corporate Internet

use policies.

The Integrated Solution The F5 and Cisco integrated solution enables organizations to intelligently manage SSL while providing visibility into

a key threat vector that attackers often use to exploit vulnerabilities, establish command and control channels, and

steal data. Without SSL visibility, it is impossible to identify and prevent such threats at scale.

Key highlights of the joint solution include:

• Flexible deployment modes that easily integrate into even the most complex architectures, consolidate

the security stack to reduce complexity, and deliver SSL visibility across the security infrastructure.

• Centralized SSL decryption/re-encryption with best-in-class SSL hardware acceleration, eliminating

the processing burden of multiple decryption/re-encryption workloads on every security inspection hop in

the stack, which reduces latency while improving the user experience.

• Dynamic security service chaining, which provides policy-based traffic management, thus determining

whether traffic should be allowed to pass or be decrypted and sent through a security device or service.



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• An industry-leading application delivery controller that load balances traffic to multiple devices in the

security services, enabling effortless scaling and growth.

• Built-in health monitors that detect security service failures and shifts, or bypasses, loads in real time

to provide reliability and fault tolerance.

• Full cipher support, including support for the perfect forward secrecy (PFS) enabled ciphers, to ensure

full traffic visibility.

• Advanced sandboxing capabilities to perform automated static and dynamic analysis, then uncover

stealthy threats and help the security team to understand, prioritize, and block sophisticated attacks.

• Point-in-time malware detection and blocking using anti-virus (AV) detection engines, one-to-one

signature matching, machine learning, and fuzzy fingerprinting.

• Global threat intelligence sharing by Cisco experts who analyze millions of malware samples and

push that intelligence to AMP to correlate against this context-rich knowledge base, which enables it to

proactively defend against known and emerging threats.

F5 SSL Orchestrator installs a decryption/clear text zone between the client and web server, creating an aggregation

(and, conversely, disaggregation) visibility point for security services.

Figure 1: The integrated F5 and Cisco Firepower security solution

SSL visibility: How do we do it? The F5 system establishes two independent SSL connections—one with the client and the other with the web server.

When a client initiates an HTTPS connection to the web server, the F5 system intercepts and decrypts the client-

encrypted traffic and steers it to a pool of Cisco Firepower devices (or devices running FirePOWER Services) for



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inspection before re-encrypting the same traffic to the web server. The return HTTPS response from the web server

to the client is likewise intercepted and decrypted for inspection before being sent on to the client.

Figure 2: The F5 full proxy architecture

SSL orchestration using security service chains A typical security stack often consists of more than advanced anti-malware protection systems. It begins with a

firewall but almost never stops there, with components such as intrusion detection/prevention systems (IDS/IPS), web

application firewalls, data loss prevention (DLP), and more. To solve specific security challenges, security

administrators are accustomed to manually chaining these multiple point security products by creating a bare-bones

security stack consisting of multiple services. In this model, all user sessions are provided the same level of security,

as this “daisy chain” of services is hard-wired.

As shown in Figure 3, SSL Orchestrator can load balance, monitor, and dynamically chain security services, including

next-gen firewalls, DLP, IDS/IPS, web application firewalls, and anti-virus/malware, by matching the user-defined

policies to determine whether to bypass or decrypt and whether to send to one set of security services or another.

This policy-based traffic steering capability allows for better utilization of the existing security services investment and

helps to reduce administrative costs.



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Figure 3: The security service chaining architecture

The F5 SSL visibility solution provides a way to apply different service chains based on context derived from a

powerful classification engine. That context can come from:

• Source IP/subnet.

• Destination IP/subnet.

• IP intelligence category.

• IP geolocation.

• Host and domain name.

• URL filtering category.

• Destination port.

• Protocol.

Deployment Planning Careful advance consideration of deployment options can ensure an efficient and effective implementation of the F5

integrated solution using the Cisco Firepower security system.

Sizing The main advantage of deploying SSL Orchestrator in the corporate security architecture is that the wire traffic now

can be classified as “interesting” traffic, which needs to be decrypted by SSL Orchestrator for inspection by Cisco



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Firepower, and “uninteresting” traffic, which is allowed to pass through or be processed differently according to other

corporate policy requirements. This selective steering of only the interesting traffic to the firewall system conserves its

valuable resources (as it need not inspect the entire wire traffic), maximizing performance.

As a result, it is important to consider the entire wire traffic volume to calculate the appropriate F5 device size.

Depending on the mode of deployment you choose, you will need at least two interfaces on the F5 system for each

firewall configured for inline mode and at least one interface for each firewall configured for TAP mode.

Refer to the SSL Orchestrator Datasheet and consider the following factors when sizing the F5 system for the

integrated solution:

• Port density

• SSL bulk encryption throughput

• System resources

• The number of security services and devices in them

License components F5 SSL Orchestrator hardware—the i2800, i5800, i10800—supports this integration. By default, SSL Orchestrator

ships with an installed base module that provides both SSL interception and service chaining capabilities.

SSL Orchestrator can also be deployed as an application on an existing F5® BIG-IP® system. Please contact your

local F5 representative to understand the licensing and deployment options. For simplicity’s sake, references to SSL

Orchestrator and the BIG-IP system in this document (and some user interfaces) apply equally regardless of the F5

hardware used. The solution architecture and configuration are identical.

Optionally, customers can consider the following:

• A URL Filtering (URLF) subscription to use the URL category database for filtering.

• An F5 IP Intelligence subscription to detect and block known attackers and malicious traffic.

• A network hardware security module (HSM) to safeguard and manage digital keys for strong

authentication.

Cisco Firepower can be deployed:

• Via Firepower Threat defense (a unified software image) on the ASA 5000x and Firepower 2100/4100/9300

platforms.

• Via FirePOWER services on a separate FirePOWER module on an ASA ASA 5500x platform.

Horizontal scaling SSL Orchestrator’s ability to steer and load-balance traffic to multiple security devices in a service or service pool

enables the Cisco security platform to scale horizontally without the need for any functional add-on. This ensures that

the service is not only fault-tolerant but also highly available, maximizing throughput.

https://www.f5.com/pdf/products/herculon-ssl-orchestrator-datasheet.pdf



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It is common to configure a single pool of Cisco Firepower NGFWs with SSL Orchestrator load balancing the

unencrypted HTTP and decrypted HTTPS traffic to all the pool members. However, if you need to create multiple

firewall pools, each taking a different traffic set based on user-defined criteria such as VLAN, tenant, or other criteria,

you can do so by leveraging the TCP Service Chain Classifier Rules in SSL Orchestrator. These rules classify the

wire traffic based on user-defined network information, IP geolocation, URL category, protocol, or IP intelligence,

among other factors, and steer the classified traffic accordingly to a designated service chain the Cisco Firepower

pool is part of.

Border Router

Floating IP

Floating IP

Service Pool-1

F5 Ingress

F5 Egress

Service Pool-2

Clients

Figure 4: Cisco Firepower NGFWs in a service/service pool scaling configuration horizontal with SSL Orchestrator

Traffic exemptions for SSL inspection As noted, SSL Orchestrator can be configured to distinguish between interesting and uninteresting traffic for the

purposes of security processing. Examples of uninteresting traffic (including those types that cannot be decrypted) to

be exempted from inspection may include:

• Guest VLANs.

• Applications that use pinned certificates.

• Trusted software update sources like Microsoft Windows updates.

• Trusted backup solutions like a crash plan.

• Any lateral encrypted traffic to internal services to be exempted.



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You can also exempt traffic based on domain names and URL categories. The service chain classifier rules of SSL

Orchestrator enable administrators to enforce corporate Internet use policies, preserve privacy, and meet regulatory

compliance.

Traffic exemptions based on URL category might include bypasses (and thus no decryption) for traffic from known

sources of these types of traffic:

• Financial

• Health care

• Government services

Certificate requirements An SSL certificate—preferably a subordinate certificate authority (CA)—and private key on SSL Orchestrator are

needed to generate and issue certificates to the end host for client-requested HTTPS websites that are being

intercepted.

To ensure that clients on the corporate network do not encounter certificate errors when accessing SSL-enabled

websites from their browsers, the root certificate must be imported into the browser or operating system of the end

hosts.

IP addressing When a Cisco Firepower NGFW is deployed as an L3/routed hop, we recommend configuring its IP addresses for

connected inward and outward VLANs from default fixed addressing subnets, provided by SSL Orchestrator, that are

derived from a RFC2544 CIDR block of 192.19.0.0. This minimizes the likelihood of address collisions.

For example, you can configure a firewall to use the IP address 198.19.0.61/25 on the inward VLAN and

198.19.0.161/25 on the outward VLAN pointing to the F5 connected interfaces. You will also need to configure static

routes to the internal networks on the firewall inward VLAN and a default route to the Internet on the outward VLAN.

The table below explains the IP addresses that you need to configure when deploying multiple firewalls in the service

pool.

Cisco Firepower NGFW

Inward Interface IP

Inward / Internal Gateway

Outward Interface IP

Outward/ Default Gateway

Cisco Firepower

NGFW-1

198.19.0.61/25

198.19.0.10/25

198.19.0.161/25

198.19.0.245/25

Cisco Firepower

NGFW-2

198.19.0.62/25 198.19.0.162/25

Cisco Firepower

NGFW-n

n 8

198.19.0.6n/25 198.19.0.16n/25

n 8



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Deployment modes Due to security concerns around key compromise, Internet sites have started to move away from RSA-based

encryption. RSA, as a key exchange encryption protocol, uses the server’s key pair to negotiate the symmetric keys

used in the encrypted session, therefore potentially compromising the server’s private key (such as in the Heartbleed

vulnerability), as well as compromising any message, current or past, that uses or used that key pair. Therefore,

these websites are transitioning to encryption technologies based on Diffie-Hellman (DH) key agreement protocols

that do not expose data if a private key is compromised. Further, making DH keys ephemeral (temporary) defines that

cryptography as perfect forward secrecy (PFS). PFS protects past sessions against future compromise of the secret

keys, as they are not linked to the server’s key pair.

An interesting side effect of this evolution is that passive SSL inspection technologies—systems that exist in the

market today and can attach to a span port to passively (and often asynchronously) decrypt SSL/TLS

communications—can no longer function. These technologies rely on the client and server performing an RSA key

exchange, and they must possess a copy of the server’s private key. If the client and server choose a PFS cipher,

there is no opportunity for these passive SSL systems to decrypt the data. Many Internet sites and most browsers

today prefer PFS ciphers over non-PFS (RSA) ciphers. In addition, the newest TLS version 1.3 update will completely

remove non-PFS key exchanges, making passive SSL systems nonfunctional. In other words, to perform SSL

visibility when employing ciphers based on PFS, an intercept system must be inline to the traffic flow.

Within that provision, various modes of deployment are available for integrating F5 systems with Cisco Firepower

firewalls for advanced threat protection.

Single or double F5 systems

The F5 SSL visibility solution with inline Cisco Firepower NGFWs can be deployed with one or two F5 systems.

• Option 1: A single F5 system with inline Cisco Firepower NGFW. This solution entails a single F5

system deployed to perform both decryption and re-encryption of SSL traffic, while Cisco Firepower

NGFWs are configured for inline mode and deployed as an L3 service pool on the F5 system.

• Option 2: Two F5 systems with inline Cisco Firepower NGFW. Although a single F5 system delivers

all the capabilities and functionality needed to deploy the SSL visibility solution, in some cases,

customers may want to implement a second F5 system on the egress:

o When there is a need for increased SSL throughput of the solution, or

o When the organization’s security policy dictates deploying two SSL intercept appliances for visibility.

When using two F5 systems for the SSL visibility solution, the ingress system on the client side will decrypt the

client-encrypted web traffic, while the egress system on the server/Internet side will re-encrypt the same traffic

before sending it to the web server, maximizing SSL throughput.

Service pool or sandwich

Deploying the SSL visibility solution using two F5 systems entails two options for configuring the Cisco Firepower

NGFWs:



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• As a service pool managed on the ingress F5 system. The advantage of deploying firewalls in a

service pool is that the ingress F5 system can then steer traffic based on user-defined service chain

policies.

• With the pool sandwiched between the ingress and egress F5 systems. While this type of

deployment allows the F5 system to steer unencrypted traffic that has traveled through the service

chains to the sandwiched firewalls in the decrypt zone, it has the downside of limiting policy enforcement,

as the firewall pool is no longer a part of any services chain. Further, it also complicates the failover

design. The firewalls now need to be configured to fail open, as the decrypt zone has no built-in way to

go around device failures here.

Both of these mode options are valid for outbound flows (for example, corporate users browsing the web over

HTTPS). They are also applicable at any data exchange points in the data center where the encrypted traffic flows

outbound from one security zone to another.

Architecture best practices

A number of best practices can help ensure a streamlined architecture that optimizes performance and reliability as

well as security. F5 recommendations include:

• Deploy the F5 systems in a sync/failover device group (S/FDG), which includes the active-standby pair, with

a floating IP address for high availability (HA).

• Every Cisco Firepower NGFW in the service pool must be dual-homed on the inward and outward VLANs

with each F5 system in the device sync/failover device group.

• Further interface redundancy can be achieved using the Link Aggregation Control Protocol (LACP). LACP

manages the connected physical interfaces as a single virtual interface (aggregate group) and detects any

interface failures within the group.

• Unlike with some competing solutions, the F5 systems do not need physical connections to the Cisco

Firepower NGFWs. All the F5 system requires is L3 reachability to steer traffic through the firewalls. In slow

networks, however, we recommend deploying the firewalls not more than one hop away. As a generic

guideline, when inspection devices are not directly connected to the F5 system, we highly recommend use

of network and VLAN controls to restrict access to the unencrypted data only to the inspection devices. For

the same reason, RFC2544 addresses mandated by SSL Orchestrator provide that extra level of security

control at the network layer.

Initial Setup Initial setup includes configuration of Cisco Firepower on ASA and setup of SSL Orchestrator. Once these steps are

complete, you can proceed to configuration for the specific deployment scenario you choose.

https://support.f5.com/kb/en-us/products/big-ip_ltm/manuals/product/tmos-implementations-11-2-0/2.html



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Configure Firepower

The deployment modes explained in this document were validated on a Cisco ASA 5500x platform running

FirePOWER Services as a separate application on the FirePOWER module. These deployment modes are also

applicable for platforms running the Firepower Threat Defense unified software. Refer to the Cisco ASA FirePOWER

Module Quick Start Guide and configuration guides to configure Cisco FirePOWER and register the Cisco FireSIGHT

Management Center.

Run the SSL Orchestrator Setup Wizard After you plug in the power supply to the F5 device, the first things to set up are the management IP address,

netmask, and default routing from the command line of your system. (Note: The Setup Wizard is substantially the

same regardless of whether you are deploying SSL Orchestrator on an existing or new F5 system. The only

exceptions are a few configuration items, such as SSL certificate configuration, that readily can be performed

manually on current systems.)

Figure 5: Initial configuration of the management IP from the command line

Log in to the web UI using the configured management IP address (default web interface credentials are

admin/admin). The SSL Orchestrator Setup Wizard guides you through the basic, minimal setup configuration for F5

SSL Orchestrator.

Note: If at any time during configuration you need to return to the SSL Orchestrator Set-Up Wizard, simply click the

F5 logo in the upper-left corner of the Configuration utility, and on the Welcome screen, click Run the Setup Utility.

1. On the F5 Welcome screen, click Next.

2. On the License screen, click Activate.

3. On the EULA screen, click Accept. The license activates and the system reboots.

4. Once the system has rebooted, click Continue.

5. On the Device Certificates screen, click Next.

6. Once the Platform screen appears, complete the following steps:

i. Enter the Host Name for this system. The Host Name must be a fully qualified domain name.

http://www.cisco.com/c/en/us/td/docs/security/asa/quick_start/sfr/firepower-qsg.html

http://www.cisco.com/c/en/us/td/docs/security/asa/quick_start/sfr/firepower-qsg.html

http://www.cisco.com/c/en/us/support/security/firepower-ngfw/products-installation-and-configuration-guides-list.html



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ii. Under User Administration, enter and confirm the Root Account and Admin Account

passwords, and click Next. The Root Account provides access to the command line, while the

Admin Account accesses the user interface.

Figure 6: Platform configuration

7. The system notifies you to log out and then log back in with your username (admin) and new password.

Click OK. The system reboots.

8. Once the Network Time Protocol (NTP) configuration screen opens, enter the IP Address of the NTP

server to synchronize the system clock with, and click Add. Click Next.

9. (Optional, unless you plan to later use the DNSSEC option in the SSL Orchestrator configuration—in

which case this step is required.) The Domain Name Server (DNS) screen opens. Complete the following

steps:

i. To resolve host names on the system, set up the DNS and associated servers: For the DNS

Lookup Server List, type the IP Address of the DNS server and click Add.

ii. If you use BIND servers, add them in the BIND Forwarder Server list.

iii. Add local domain lookups (to resolve local host names) in the DNS Search Domain list.

iv. Click Next. The Internal VLAN screen opens.

10. On the Internal VLAN screen, specify the Self IP settings for the internal network:

i. Enter a self IP Address.



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ii. Enter a network mask (Netmask) for the self IP address.

iii. Retain the default values for the Port Lockdown and VLAN Tag ID settings.

iv. Under Interfaces, select an interface number from the VLAN Interfaces list, and then select

Tagged or Untagged from the Tagging list. (Select Tagged when you want traffic for that interface

to be tagged with a VLAN ID.) Click Add.

v. Click Next. This completes the configuration of the internal VLAN.

Figure 7: Internal VLAN configuration

11. The External VLAN screen opens. Specify the Self IP settings for the external network:

i. Enter a self IP Address.

ii. Enter a network mask (Netmask) for the self IP address.

iii. Retain the default value for the Port Lockdown setting.

iv. Enter the IP address you want to use as the Default Gateway to the external VLAN.

v. Retain the default value (auto) for the VLAN Tag ID setting. Click Next. This completes the

configuration of the external self IP addresses and VLAN.

12. On the Forward Proxy Certificate screen, complete the following configuration to import the CA

certificate:

i. For the Certificate Name, select Create New and enter a name.

ii. For the Certificate Source, either select Upload File and choose a file, or select Paste Text and

use copy and paste to enter your certificate source.

iii. For the Key Source, either select Upload File and choose a file, or select Paste Text and use

copy and paste to enter your key source.



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iv. If your certificate/key source is protected by a passphrase, select Password as the Security Type,

and enter the passphrase. Otherwise leave the default setting. Click Next.

13. On the Logging screen, select either local or Splunk as the Publisher Type.

• If you select local, specify the Destination—either local-db or localsyslog. This determines the

destination of your logs, either a local database or a localsyslog server.

• If you select Splunk, for Protocol, select either TCP or UDP. Enter the IP Address and Port of the

Splunk server.

14. Click Finish. The SSL Orchestrator configuration page appears with a complete menu displayed on the

left side of the page.

Figure 8: The SSL Orchestrator configuration screen once the initial setup is complete

You are now ready to proceed to the second part of configuration, where you finalize your system for SSL

Orchestrator.

Update the SSL Orchestrator version Periodic updates are available for the SSL Orchestrator configuration utility. To download the latest, follow these

steps:

1. Visit downloads.f5.com. You will need your registered F5 credentials to log in.

2. Click Find a Download.

3. Scroll to the Security product family and select SSL Orchestrator.

http://downloads.f5.com/



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Figure 9: F5 product download web page

4. Click the SSL Orchestrator container.

5. Select and download the latest version of the SSL Orchestrator .rpm file.

6. Read through the appropriate Release Notes before attempting to use the downloaded file.

7. Once you’ve read the release notes, log in to the main tab of the F5 system management interface and

navigate to SSL Orchestrator > Updates.

8. Under File Name, click Browse and navigate to the .rpm file you saved on your system. Click Open to

select it.

Figure 10: Updating SSL Orchestrator

9. Click Install. The latest version of the SSL Orchestrator configuration utility will be installed. Your system

may reboot to make the change effective.

https://downloads.f5.com/esd/releaseNotes.jsp



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Back up your F5 system configuration Before beginning the detailed SSL Orchestrator configuration, we strongly recommend you back up the F5 system

configuration using the following steps. This enables you to restore the previous configuration in case of any issues.

1. From the main tab of the F5 management interface, click System > Archives.

2. To initiate the process of creating a new UCS archive (backup), click Create.

3. Enter a unique File Name for the backup file.

4. Optional:

• If you want to encrypt the UCS archive file, from the Encryption menu, select Enabled and enter a

passphrase. You must supply the passphrase to restore the encrypted UCS archive file.

• If you want to exclude SSL private keys from the UCS archive, from the Private Keys menu, select

Exclude.

Figure 11: New system archive creation

5. Click Finished to create the UCS archive file.

6. When the backup process is done, examine the status page for any reported errors before proceeding to

the next step.

7. Click OK to return to the Archive List page.

8. Copy the .ucs file to another system.

To restore the configuration from a UCS archive, navigate to System > Archives. Select the name of the UCS file

you want to restore and click Restore. For details and other considerations for backing up and restoring the F5

system configuration, see Solution K13132 on AskF5: Backing up and restoring configuration files.

https://support.f5.com/csp/article/K13132



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Configuration for a Single F5 System with FirePOWER Services on Cisco ASA in L2 Mode (Burrito Design) This deployment mode entails a single F5 system performing SSL visibility. This single system handles both

decryption and re-encryption of HTTPS traffic, with an inspection zone installed between the ingress and the egress.

Figure 12 shows a standalone F5 system configured to intercept, decrypt, and steer the decrypted traffic to a service

pool of two Cisco FirePOWER Services modules on ASAs configured in L2 mode where the traffic will be inspected

for hidden threats. You can also deploy the F5 system as a device sync/failover device group (including an HA pair)

with a floating IP address for high availability.

Internet

ICAP

Mirrored-Traffic Monitors

L3 Inspection Devices

F5 System

Service Chains

1

2 3

4

Corporate Data Center

Corporate Office Users

Cisco FirePOWERservice pool

Figure 12: The SSL visibility solution with a pool of Cisco ASAs in a service chain using one F5 system

How traffic flows in this deployment option:

1. Client traffic arriving at the ingress F5 device is classified, and interesting HTTPS traffic is decrypted as

part of the SSL forward proxy process.

2. The ingress virtual servers on the F5 system steer the decrypted traffic through a service pool of Cisco

ASAs as part of a service chain via a service-inward VLAN.

3. The HTTP traffic is inspected by the FirePOWER Services for any hidden threats before sending that

traffic back to the F5 system on the service-outward VLAN.



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4. The F5 system orchestrates the decrypted traffic through other services in the chain before it aggregates

and re-encrypts the traffic, which is routed outbound to the web server.

Configure SSL Orchestrator In the example configuration below, SSL Orchestrator steers the outbound web traffic through the Cisco ASAs, which

are part of a service chain of security devices. Please refer to the F5 SSL Orchestrator Setup Guide for additional

help during configuration.

General properties

This first step must be completed before you can set up services, service chains, and classifier rules.

1. On the main screen of the management console, click SSL Orchestrator > Configuration > General

Properties.

2. Answer the configuration questions (see Figure 13) for SSL Orchestrator. (Also see the table below for

examples and tips.)

Question User Input

Application Service Name Enter a name without spaces or dashes for the SSL Orchestrator application.

Do you want to set up separate

ingress and egress devices with a

cleartext zone between them?

You can configure a single F5 device to receive both ingress and egress traffic on

different networks, or you can configure separate F5 devices for ingress and

egress traffic. If you choose the latter option, you are asked further questions to

enter peer application names, control channel virtual server IPs, and pre-shared

keys to establish and protect the communication between the devices.

Otherwise, select No, use one BIG-IP device for ingress and egress. (Select

this option even if you are using new SSL Orchestrator hardware.) This sample

configuration follows that option.

Which IP address families do you

want to support?

Select Support IPv4 only. (Currently SSL Orchestrator only supports IPv4

families.)

Which proxy schemes do you

want to implement?

SSL Orchestrator can operate in transparent and/or explicit proxy mode. If you

choose explicit proxy, a separate explicit proxy configuration section displays for

you to choose the VLANs that explicit proxy needs to listen to and so you can

enter the IP address and port number of the explicit proxy.

Select Implement Transparent proxy only.

Do you want to pass UDP traffic

through the transparent proxy

unexamined?

This option only applies if you selected Implement transparent proxy only

above. By default, transparent proxy mode manages TCP traffic but allows UDP

traffic to pass through unexamined. Choose No to prevent the passage of

unexamined UDP traffic.

Otherwise, select the default, Yes, pass all UDP traffic unexamined.

Do you want to pass non-TCP,

non-UDP traffic through the

transparent proxy?

This option also only applies if you select Implement transparent proxy only. By

default, transparent proxy mode passes through non-TCP, non-UDP traffic (such

as IPSec, SCTP, and OSPF). Choose No to block.

Otherwise, select the default, Yes, pass non-TCP, non-UDP traffic.

https://support.f5.com/kb/en-us/products/ssl-orchestrator/manuals/product/f5-herculon-ssl-orchestrator-setup-13-0-0.html



20

Which is the SSL Forward Proxy

CA certificate?

Select the Certificate Authority (CA) certificate that your clients will trust to

authenticate intercepted TLS connections. If you did not use the Setup Wizard,

you must import a CA certificate before you can use this functionality.

Which is the SSL Forward Proxy

CA private key?

Select the corresponding private key, which you imported with the CA certificate

while configuring the Setup Wizard. If you did not use the Setup Wizard, you must

import a CA certificate before you can use this functionality.

What is the private-key

passphrase (if any)?

Enter the private-key passphrase, if any. If the key does not have a passphrase,

leave this field empty.

Which CA bundle is used to

validate remote server

certificates?

The CA bundle is the collection of root and intermediate certificates for the CA

you trust to authenticate servers where your clients might connect. The CA bundle

is also known as the local trust store.

Select the CA bundle that validates the remote server certificates.

Should connections to servers

with expired certificates be

allowed?

Remote servers can present expired certificates. Allowing connections to servers

with expired certificates can cause a security risk. Legitimate servers do

sometimes offer certificates which are overdue for renewal or which were signed

by legitimate CAs but that are simply unknown to the F5 system. In the latter

case, if you allow connections, consider adding any needed CA certificates to the

F5 system CA bundle (trust store).

Select No, forbid connections to servers with expired certificates to prevent

connections to servers that have expired certificates.

Should connections to servers

with untrusted certificates be

allowed?

Remote servers can present untrusted certificates. Allowing connections to

servers with untrusted certificates can cause a security risk.

Select Yes, allow connections to servers with untrusted certificates if

appropriate for your situation and security policies.

Should strict updates be enforced

for this application?

If you select this option, you cannot manually modify any settings produced by the

application. Once you disable this option, you can manually change your

configuration.

F5 recommends enabling this setting (select Yes) to avoid misconfigurations that

can cause an unusable application.



21

Figure 13: Sample general properties configuration

3. Continue configuration by scrolling down to Ingress Device Configuration (see below.)

Ingress device configuration

The ingress device is one or more ingress VLANs where clients send traffic. The F5 device decrypts the encrypted

traffic on ingress and then, based on protocol, source, and destination, classifies the traffic and passes each

connection for inspection.

1. Answer each configuration question. See tips and guidance below.

Question User Input

Which VLAN(s) will bring client

traffic to the transparent proxy?

Select one or more VLANs where transparent-proxy ingress traffic will arrive.

How should a server TLS

handshake failure be handled?

Most TLS handshake failures occur during protocol and cipher agreement. You

can specify whether to drop or bypass the connection.

Typically, select If server TLS handshake fails the connector fails.

DNS query resolution Specify whether to permit the system to send DNS queries directly to the Internet,

or specify one or more local forwarding nameservers to process all DNS queries

from SSL Orchestrator. If you choose the former, you can specify to configure

local/private DNS zones.

In this example, select Send DNS queries to forwarding nameservers on the

local network.



22

Which local forwarding

nameserver(s) will resolve DNS

queries from this solution?

Type the IP address of the local nameserver(s) which will resolve the DNS

queries.

Do you want to use DNSSEC to

validate DNS information?

DNSSEC is a suite of extensions that add security to the DNS protocol by

enabling DNS responses to be validated.

Select Yes, use DNSSEC to validate DNS information.

Figure 14: Sample ingress device configuration

2. Continue configuration by scrolling down to Egress Device Configuration (see below.)

Egress device configuration

The egress device is one or more egress VLANs where the clients receive traffic. The F5 system decrypts the

encrypted response on egress and then, based on protocol, source, and destination, classifies the traffic and passes

each connection for inspection before sending it to the requested internal client.

1. Answer each configuration question. Note that in this example, the same F5 device is configured to

receive both the ingress and egress traffic.

Question User Input

Do you want to SNAT client IP

addresses?

It is common to translate the client source IP address with the address belonging

to the egress for outbound traffic. Choose No to preserve the client source IP

address.

Otherwise, select Yes, SNAT (replace) client addresses

Do you want to use a SNAT Pool? F5 recommends use of a SNAT pool to scale translations instead of overloading

the egress interface IP address (AutoMap).

Select Yes, define SNAT Pool addresses for good performance.

IPv4 SNAT addresses Enter the IPv4 addresses for the SNAT pool.



23

Should traffic go to the Internet

via specific gateways?

Specify whether to route outbound using the default route on the F5 system or

enter the IP address to be used as the default gateway.

In the example above, we selected No, send outbound / Internet traffic via the

default route.

Figure 15: Sample egress device configuration

2. Continue configuration by scrolling down to Logging Configuration (see below.)

Logging configuration

1. Answer the configuration questions using the guidance below.

Question User Input

What SSL Intercept logging level

do you want to enable?

F5 recommends leaving the logging level at the default, Errors. Log on

functional errors, unless you need to troubleshoot.

Which Log Publisher will process

the log messages?

Specify whether to process the logs with an existing log publisher or that logs

should be sent to syslog-ng.

What kind of statistics do you

want to record?

Specify the kind of statistics you want the system to record. SSL Orchestrator can

collect usage data for connections, service chains, services, and more. For

optimal performance, keep the settings at the default, Usage counters only.

Figure 16: Default logging settings

2. When you’re done, click Save at the top of the page.

Create layer 2 inline service Note: Before creating inline services, you must complete configuration of all the sections in the General Properties

tab.



24

Inline services pass traffic through one or more firewalls at layer 2 or layer 3. The firewalls are configured to

communicate with the F5 system via two VLANs. In this section, we will configure an L2 inline service for a pair of

Cisco ASAs.

1. On the main tab, click SSL Orchestrator > Configuration > Inline Services. The Inline Services screen

displays.

2. Click Add.

3. Enter information for the configurable fields, following the guidance below.

Configuration Field User Input

Name Type a Name for the inline service.

Service Type Select Layer 2 from the Service Type list.

Interfaces Select the From BIG-IP and To BIG-IP system interfaces connected to the

firewall and their respective VLANs Tags. Click Add.

If you have multiple firewalls in the service pool, choose the F5 system interfaces

connected to each firewall and their VLANs tags and click Add before moving to

the next one.

If you choose to use the Ratio field, the F5 system distributes connections among

pool members in a static rotation according to ratio weights that you define. For

example, if you have two devices, and one handles twice as much traffic as the

other, you can set the ratio to 1 on the smaller device and 2 on the larger one.

Translate port for HTTP traffic Select Use No if the connections should use their original destination ports.

Choose Yes to translate the port for HTTP traffic to either 80, 8080, or 8443.

Connection Handling On Outage Select Skip Service to allow connections to skip the service you are configuring if

all the devices in the service pool are unavailable.

Or select Reject Connection to reject every connection reaching the service

when the service is down.

Figure 17: Inline layer 2 service configuration

4. Leave other inline services configurations at their default settings.

5. When done, click Finished, then click Save at the top of the page.



25

Configuration for an F5 System with FirePOWER Services on Cisco ASA in L3 Mode This deployment is similar to the solution explained above in the section called, “Configuration for a Single F5 System

with FirePOWER Services on Cisco ASA in L2 Mode.” The only difference is that the inline service type is configured

as an L3 service.

ICAP



F5 System

Service Chains

192.19.0.127/25192.19.0.0/25VLAN101 VLAN201

.61 .161

.62 .162

G/W:192.19.0.248G/W:192.19.0.1Corporate Data Center


Internet


Figure 18: The SSL visibility solution with Cisco ASAs configured in L3 mode

Create the layer 3 inline service The layer 3 inline service, as a prerequisite, requires you to configure the IP addresses on the firewall(s) from a

specific fixed addressing scheme as explained in the section on IP addressing. This configuration enables the F5

system to send to, and receive from, the firewall using a pre-defined set of addresses.

1. On the main tab, click SSL Orchestrator > Configuration > Inline Services.




26


What is the IPv4 (CIDR /19)

subnet-block base address?

For IPv4, F5 recommends the default block 198.19.0.0/19. Click Add.

Even though you can change the base address of each address block (IPv4) from

which subnets and addresses are assigned, changing an address block has

several implications, must be done with caution, and is not recommended or

supported by F5.

Name Enter a Name for the inline service.

Service Type Select Layer 3 from the Service Type list.

Interfaces Select From BIG-IP and To BIG-IP system interfaces connected to the firewall(s)

and their respective VLANs Tags.

Available Devices Select the IP Address(es) of the firewall(s).

In the sample configuration in Figure 19, the two configured IP addresses on each

of the firewalls in the service pool are selected. These firewalls are preconfigured

from the CIDR block of 192.19.0.0.

Translate port for HTTP traffic Select No if the connections should use their original destination ports.

Choose Yes to translate the port for HTTP traffic to either 80, 8080, or 8443.

Connection Handling On Outage Select Skip Service to allow connections to skip the service you are configuring if

all the devices in the service pool are unavailable.

Or select Reject Connection for the system to reject every connection reaching

the service when the service is down.

Figure 19: Inline layer 3 service configuration


Configuration for the F5 System with Cisco ASAs in TAP Mode In this solution option, the F5 system is configured to provide a packet-by-packet copy of both the unencrypted HTTP

and decrypted HTTPS traffic to Cisco ASAs wherein the Cisco FirePOWER Services are configured for TAP mode.



27

F5 System

ICAP



Service Chains

Cisco ASA-2



Internet

Receive Only Services

Cisco ASA-1

Figure 20: The SSL visibility solution for Cisco ASAs in TAP mode

Create a receive-only service When firewalls are configured for receive-only service, they only receive traffic for inspection and do not send the

traffic back to the F5 system. You can configure up to 10 receive-only services using the SSL Orchestrator

configuration utility.

1. On the main tab, click SSL Orchestrator > Configuration > Receive Only Services.



Name Enter a Name for the receive-only service.

MAC Address Enter the receiving interface’s MAC Address. The MAC address can be obtained

from the web UI.

IP Address Enter the nominal IP Address for this device. Each receive-only device requires a

nominal IP host address to identify the device in the F5 system.

This nominal IP address must be homed on the same subnet as one (any one) of

the F5 system’s self-IP addresses. It does not have to be on the same VLAN as

the receive-only device. No IP packets will ever be sent to the nominal IP address

(but it must be unique on the network while it is assigned in this solution).

VLAN From the VLAN list, select the VLAN where the receive-only device resides.

Interface Select the associated F5 system Interface.



28

Figure 21: Sample receive-only service configuration


Alternative Architectures As explained in the Deployment Modes section, you may want to deploy a second F5 device for various reasons.

These alternative architectures require a few additional configuration steps.

Two F5 systems with ASAs deployed as a service pool This solution is similar to the one explained in the section called, Configuration for a Single F5 System with Cisco

FirePOWER Services in L2 Mode. The only difference is that a second F5 device (the egress device) is introduced to

offload re-encryption from the ingress device.

ICAP



Control Channel

Service Chains

F5 EgressF5 Ingress



Internet

Cisco FirePOWER service pool

Figure 22: The SSL visibility solution with security service chaining using two F5 systems

Additional configuration steps

For this deployment scenario, you must configure SSL Orchestrator separately on the ingress and egress F5 devices

to enable them to cooperate via a control channel. At least a /30 CIDR block is needed for IP connectivity of the

control channel virtual servers on the F5 systems.



29

Configure the ingress F5 device: General properties

The ingress device is either an F5 device or a sync/failover device group where each client sends traffic. The ingress

device is one or more ingress VLANs where the clients send traffic. The ingress device decrypts the traffic and then,

based on protocol, source, and destination, classifies the traffic and passes each connection for inspection.

1. On the main tab, click SSL Orchestrator > Configuration > General Properties.

2. Enter information for the additional configurable fields that are specific to configuring separate ingress and

egress devices. Follow the guidance below.

Question User Input

Application Service Name Enter a name without spaces or dashes for the SSL Orchestrator application

service.

Do you want to setup

separate ingress and egress

devices with a cleartext zone

between them?

Select Yes, configure separate ingress and egress BIG-IP devices.

Is this device the ingress or

egress device?

Select This is the INGRESS device to which clients connect.

What is the EGRESS device

Application Service name?

Enter the name of the SSL Orchestrator application service you intend to configure

on the egress device. For the sake of ease, you can use the same SSL Orchestrator

application service name on both the ingress and egress devices.

What is the IP address of the

EGRESS device control-

channel virtual server?

Enter the IP address of the control channel virtual server over on the egress device.

What IP address should THIS

(ingress) device's control-

channel virtual server use?

Enter the IP address of the virtual server for the control channel.

What is the control-channel

pre-shared key?

Enter a pre-shared key (PSK) value to enable cryptographic protection of the service

chain control channel between the ingress and egress F5 devices.

Figure 23: Sample general configuration when ingress and egress devices will be separate



30

3. Continue configuration with the decryption zone configuration below.

Configure the ingress F5 device: Decryption zone to egress device configuration

1. Once you’ve completed the additional General Properties configuration, continue to scroll down the page

and answer the following configuration question, using the guidance below.

Question User Input

Are there parallel service devices

in the decrypt zone?

Select No, send outbound traffic via the BIG-IP default route(s).

Or select Yes when firewalls will be sandwiched in the decrypt zone between the

ingress and egress devices.


Configure the egress F5 device: General properties

The egress device is either an F5 device or a sync/failover device group that receives traffic that has traveled through

the specified service chain and directs that traffic to the final destination. The ingress and egress devices also send

each other control messages that can go through the decrypt zone or around it, if you configure a different path

through the network. In either case, the messages are sent through TCP connections to port 245, at an IP address

users specify, on each F5 system.

1. On the main tab, click SSL Orchestrator > Configuration > General Properties.

2. Enter information for the additional configurable fields that are specific to separate ingress and egress

devices. Follow the guidance below.

Question User Input

Application Service Name Enter a name without spaces or dashes for the SSL Orchestrator application

service.

Do you want to setup separate

ingress and egress devices with

a cleartext zone between them?

Select Yes, configure separate ingress and egress BIG-IP devices.

Is this device the ingress or

egress device?

Select This is the EGRESS device which connects to a server.

What is the INGRESS device

Application Service name?

Enter the name for the SSL Orchestrator application service configured on the

ingress device.

What is the IP address of the

INGRESS device control-channel

virtual server?

Enter the IP address of the control channel virtual server on the ingress device.

What IP address should THIS

(egress) device's control-channel

virtual server use?

Enter the IP address of the virtual server for the control channel.



31

What is the control-channel pre-

shared key?

Enter a pre-shared key (PSK) value to enable cryptographic protection of the

service chain control channel between the ingress and egress devices.

3. Continue configuration with the decryption zone configuration below.

Configure the egress F5 device: Egress device configuration

1. Once you’ve completed the additional General Properties configuration, continue to scroll down the page

and answer this additional configuration question using the guidance below.

Question User Input

Which VLAN(s) are part of the

decrypt zone? (These bring traffic

from the ingress device)

Select one or more VLANs where transparent-proxy ingress traffic will arrive.

Note: If you chose Explicit proxy in the General Properties section to answer the question “Which proxy

schemes do you want to implement?” a separate explicit proxy configuration section displays here

instead. In that case, choose the VLANs that explicit proxy will listen to, and enter the IP address and port

number of the explicit proxy.

Configure the egress F5 device: Decrypt zone to ingress device configuration

1. Continue to scroll down the page and answer the question, Are there parallel service devices in the

decrypt zone?

• Select No, send outbound traffic via the BIG-IP default route(s).

• Or select Yes when firewalls will be sandwiched in the decrypt zone between the ingress and egress

devices.


Two F5 systems with firewalls sandwiched in the decryption zone In this case, the Cisco ASAs are deployed as a load balancing pool between the ingress and egress F5 systems in

the decrypt zone and are not part of the service chains.



32

F5 EgressF5 Ingress

ICAP




Control Channel

Decrypt Zone



InternetCisco FirePOWER

service pool

Figure 24: The SSL visibility solution with Cisco ASAs sandwiched between two F5 systems

Additional configuration steps

This scenario requires, as a prerequisite, that you have created a pair of VLANs—one on the ingress F5 device and

another on the egress device for each Cisco ASA in the sandwiched pool. The IP addresses of each pair of VLANs

will be from the same subnet if the firewalls are configured for L2 mode and from different subnets if the firewalls are

configured in L3 mode.

Configure the ingress device: Decrypt zone to egress device configuration

1. On the main tab, click SSL Orchestrator > Configuration > General Properties. Scroll down to the

additional configuration section specific to use of a decryption zone.

Figure 25: Sample decrypt zone to egress device configuration

2. Answer the additional questions using the guidance below.

Question User Input



Select Yes, send outbound traffic via one or more service device(s).



33

What are the IPv4 decrypt zone

gateway addresses?

Enter the IP address of the outward interface of the last layer 3 devices in the

decrypt zone.

• If the firewall is configured for L2 mode, the gateway IP address is the

address on a VLAN on the next hop egress device.

• If the firewall is configured as an L3 hop, this IP address will be the

address on a VLAN on the next hop firewall.

3. Once you’ve entered an IP address, click + to add additional addresses. You can enter multiple gateways

if you have multiple firewalls and want to load balance across them.

4. Use the Ratio value to control the load balancing as desired.


Configure the egress device: Decrypt zone to ingress device configuration

1. On the main tab, click SSL Orchestrator > Configuration > General Properties. Scroll down to the

additional configuration section specific to use of a decryption zone.

Figure 26: Sample decrypt zone to ingress device configuration

2. Answer the additional configuration questions using the guidance below.

Question User Input



Select Yes, send outbound traffic via one or more service device(s).

What are the IPv4 decrypt zone

gateway addresses?

Enter the IP address of the outward interface of the last layer 3 device in the

decrypt zone.

What are the intranet networks

(subnets)?

Enter the IP address and mask-length, in CIDR format, for intranet subnet masks.

Typical IPv4 entries include 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16.

Click + as needed to add additional addresses.




34

Creating service chains to link services Before you can set up service chains, you must configure all the services (inline, ICAP, or receive-only). By default,

SSL Orchestrator steers traffic through all the security services. You can create a new service chain by defining the

service list in the preferred order of services to which traffic should be steered.

Each service chain is linked to service chain classifier rules and processes specific connections based on those

classifier rules, which look at protocol, source, and destination addresses. Additionally, service chains can include

inline, ICAP, or receive-only services, as well as any decryption zones between separate ingress and egress devices.

1. On the main tab, click SSL Orchestrator > Configuration > Policies. The policies screen displays.

2. Under Service Chains, click Add.

3. Enter a Name for the service chain.

4. In the order you want SSL Orchestrator to use to steer the traffic, select the service Type (ICAP, inline or

receive-only) and service Name and click Add. (See Figure 27.)

5. Repeat Step 4 until all services in the chain have been selected in the order you prefer.

6. When you’re done with the service chain, click Finished.

7. Repeat Steps 2 through 6 to create multiple service chains.

Figure 27: Sample service chain configuration

Creating TCP service chain classifier rules Before you create a TCP service chain classifier rule, you must create one or more service chains. Service chain

classifier rules then determine which service chains receive traffic. Each service chain classifier rule selects the

specific chain to process ingress connections. Different classifier rules may send connections to the same chain.

Each classifier has three filters that match the source IP address, the destination mode, and the application protocol.

Filters can also overlap so that the classifier that matches best determines the service chain for a specific connection.

To avoid issues with privacy concerns and adhere to regulatory compliance, some organizations might need to

enforce policies to bypass SSL destined to websites that expose personal user information, such as is the case for



35

banking, financial, or government sites. Classifier rules enable such policy implementation based on various context

filters derived from a powerful classification engine. Finally, classifier rules can also be used to reject a connection if

needed.

1. Once you’ve created a service chain, continue to scroll down the Policies page to TCP Service Chain

Classifiers.

2. Click Add and create a classifier rule, making selections and completing each field using the guidance

below.

3. The example below creates a sample TCP service chain classifier rule (as shown in Figure 28) to bypass

SSL traffic originating from any internal client on 10.10.10.0 subnet in the corporate network and destined

to any health care websites.


Name Enter a name for the TCP service classifier rule.

Phase Select the SSL/TLS phase you want:

No TLS: Match only non-TLS/SSL traffic.

Pre-Handshake: Match TLS connections before any TLS handshake, which

means you can allow a connection to bypass SSL inspection completely, without

even trying to learn the real name of the remote server. Pre-handshake rules

must reject or bypass any connections they match.

TLS Handshake: Match only at the time of the TLS handshake and never match

non-TLS traffic. The traffic is not checked again after the plaintext of a TLS

connection becomes available.

Normal: Match TLS connections at TLS handshake time and possibly again,

more specifically, after SSL Orchestrator exposes the plaintext of the TLS

connection (so you can manage HTTPS on non-standard ports, for example).

Normal rules may also match non-TLS traffic (so, for example, a single rule can

handle both HTTPS and HTTP traffic.)

Select Normal in this sample SSL bypass configuration.

Protocol Select the protocol to match: HTTP, MAIL, ALL, or Other.

Select ALL to bypass all encrypted traffic.

Source Select the source Type, either IP Address or Data Group, and then specify the

filter Value.

IP Address is either a traffic originating IP address or subnet. An explicit 0.0.0.0

will match all the traffic when IP address or subnet is not defined.

Data Group is simply a user-defined group of related elements, such as a set of

IP addresses.

Refer to the AskF5.com resource on Data groups to learn more about data

groups.

Select IP Address as the source Type to match the connection originator and

enter 10.10.10.0 in the Value field, then click Add.

https://support.f5.com/kb/en-us/products/big-ip_ltm/manuals/product/bigip-system-irules-concepts-11-6-0/6.html



36

Destination Select the destination Mode and specify the filter Type and Value, which may

include:

Address: Specify the traffic destination based on IP Address or Data Group (as

with the source filter).

Geolocation: Specify two-letter country and three-letter continent codes to match

the destination IP against the local geolocation database.

IPI: Specify the F5 IP Intelligence category or data group against which the

destination IP address's reputation is validated. An IP Intelligence subscription is

needed for the rule to evaluate against this database of known IP addresses with

questionable reputations.

Port: Specify the port or ports against which the destination port number should

be matched. The value can be “any,” one or more TCP port numbers, or ranges

like 5557-5559 (use 0 or * to match all). The chief use of this mode is to control

non-TLS traffic such as SNMP.

URLF: Specify URL filtering (URLF) categories or a data group against which the

destination URL will be matched. A URLF subscription is needed for the rule to

evaluate against the URLF database.

Name: Specify the domain name (with a unique name or using a wildcard) or data

group against which the connection’s hostname should be matched.

DDB: Specify the DNS domain name (with a unique name or using a wildcard)

against which the destination hostname indicated by the client in TLS Server

Name Indication (SNI) is matched. Refer to RFC 6066 to understand the SNI

extension for TLS. You may use DDB (dynamic domain bypass) to whitelist and

bypass traffic to servers that cause TLS handshake problems or that require TLS

mutual (client-certificate/smart-card) authentication. A URLF rule in the pre-

handshake phase will match URL filtering categories associated with the TLS SNI

hostname and otherwise behave like a DDB rule. See the example in Figure 28

below.

Select URLF as the Destination Mode, Category as the Type, and Health and

Medicine as the Value to match, if the connection is destined to any websites in

the Health and Medicine category of the URLF database. Then click Add.

Service Chain Select the name of a Service Chain (defined in the previous procedure) or an

action—either Bypass or Reject.

Select Bypass in the Service Chain selector to enforce a bypass action when

both source and destination context filters match for an outbound connection.

Figure 28: Sample TCP service chain classifier

https://tools.ietf.org/html/rfc6066



37

4. When your classifier rule configuration is complete, click Finished.

5. Repeat Steps 2 through 4 to create multiple TCP service chain classifiers.

6. If your answer to “Do you want to pass UDP traffic through the transparent proxy unexamined?” in

the General Properties configuration was “No, manage UDP traffic by classification,” you will be

presented with a UDP Service Chain Classifiers screen to create UDP rules similar to the TCP rules.

Create and configure them following the same basic principles.

7. Finally, click Deploy at the top of the page to deploy the configured SSL Orchestrator.

Handling NAT When a Cisco ASA with FirePOWER Services module is deployed as a service in the SSL Orchestrator service

chain, it is no longer the Internet edge device. So performing the network address translation (NAT) on ASA is no

longer advisable. It is also important to perform NAT of the client’s outbound traffic after it exits the ASA to the F5

egress for re-encryption. There are two ways to handle this:

• Option A: Implement NAT on the F5 system using the SNAT pool feature. (See Figure 29.) In this case,

the NAT will be performed for the client’s outbound traffic on the egress of the F5 system. In the case of

firewalls deployed as a sandwich pool using two F5 systems, NAT should be implemented on the egress

F5 system.

ICAP



F5 System

Service Chains

Gateway NAT on F5 system



Internet

Cisco FirePOWER service pool

Figure 29: NAT on the F5 system (option A)



38

Traditionally, an ASA is often implemented on the perimeter to inspect/control access to multiple protocols, and not all

of these protocols are supported by SSL Orchestrator. When this ASA is moved from the edge and configured in the

service chain to inspect decrypted traffic, any unsupported protocol traffic that goes around SSL Orchestrator is not

inspected and therefore potentially vulnerable.

The second option, Option B, represents the needed design change to overcome this challenge, as well as NAT

recommendations.

• Option B: Segregate the ASA firewall capabilities and FirePOWER Services onto two different physical

or virtual contexts, and implement NAT post re-encryption on the edge firewall while the inspection SFR

module remains part of the F5 system in the service chain. (See Figure 30.) In this case, the F5 system

can either hand off the re-encrypted packets to the edge firewall, or forward and re-route the traffic from

the edge firewall to the gateway.

ICAP



BIG-IP System


Service Chains

Gateway NAT on Firewall

Edge ASA Firewall



Internet

Figure 30: NAT on the Cisco ASA (option B)

Testing the Solution You can test the deployed solution using the following options:

• Server certificate test

Open a browser on the client system and navigate to an HTTPS site, for example, https://www.google.com.

Once the site opens in the browser, check the server certificate of the site and verify that it has been issued by

the local CA set up on the F5 system. This confirms that the SSL forward proxy functionality enabled by SSL

Orchestrator is working correctly.

• Decrypted traffic analysis on the F5 system

Perform a TCP dump on the F5 system to observe the decrypted cleartext traffic. This confirms SSL

interception by the F5 device.

tcpdump –lnni eth<n> -Xs0

https://www.google.com/



39

• Decrypted traffic analysis on the Cisco ASA

From the web UI, go to Monitoring > Packet Capture > Create, and enable a Packet Filter. Create stages to

capture packets, specify file names, and then click OK.

Download the captured file(s) and analyze the HTTP packets. The packet header and payload should be in

clear text, indicating SSL decryption. It is very important to turn off packet capture once the job completes.

Documents

The F5 SSL Orchestrator and Cisco Firepower Solution · 2018-08-14 · RECOMMENDED DEPLOYMENT PRACTICES F5 and Cisco Firepower SSL Visibility with Service Chaining 3 Introduction